underfloor heating means thermal store a good idea?

[Doctor Drivel]

look at this thread and advantages and disadvantages of thermal stores.

http://www.diynot.com/forums/viewtopic.php?p=385005#385005

 

[simond]

Most of this thread linked above was hijacked by Water Systems, aka Doctor Drivel.

The problem is that far too many people are out there knowing sweet FA, with little intelligence to analyse what is in front of them

Water Systems (Drivel) wrote this, and I would suggest that it describes him perfectly.

Believe him at your peril, he has no tools to come out and help you. Only a pile of brochures and an overactive right hand.

 

[Dan Robinson]

 

[Agile]

Believe him at your peril, he has no tools to come out and help you. Only a pile of brochures and an overactive right hand.

At his age ???

 

[kevindgas]

can't agree with the thermal store being better than unvented

the thermal store loses working temperature very quickly the minute water is drawn through it. my experience is the unvented cylinder holds a workable temperature for a longer period.

all the complaints that i have dealt with have been thermal stores that had been installed by 3 now defunct companies i have never been to a complaint about an unvented cylinder

 

[Agile]

At first sight that sounds like nonsence but I can explain what Kevin means!

An unvented is tall and thin and hot water taken from the top will be at the stored temperature until you get to the last 10% or so when some mixing occurs with the cold inlet water.

The thermal store outputs the stored heat from a coil neat the top or a pumped plate HE and the whole store contributes to that heat transfer.

If the store starts at 80 C then when half the heat has been taken out the store temp will have dropped to just 50 C. At such a low temperature the differential of about 10 C across the HE will mean that the maximum output temperature falls to just 40 C.

We have now only taken just HALF of the heat out of the store at this point! From that point on the transferred heat into the DHW will cause the output temperature to fall below 40 C which may be OK for the washing machine but is useless for baths or showers.

The useable heat output is therefore only HALF of the actual stored heat!

Some people seem to forget that aspect !!!

Tony

 

[gas4you]

No work today Tony, or like me and off sick

 

[Agile]

I usually answer phones and use computer til about 1130 most days.

Remember I repair boilers rather than install where you have to get out early.

Its not often that I get sick although I had some kind of virus for about 36 hours about six months ago and had to stay in bed for a whole day!

Tony

 

[gas4you]

I've had to postpone an install this week, but even though i feel a rough as hell I will still have to attend call outs, which unfortunatley keep coming in Letting all calls go to voicemail and vetting first.

At least breakdowns are light work

 

[Doctor Drivel]

Most of this thread linked above was hijacked by Water Systems, aka Doctor Drivel.

The problem is that far too many people are out there knowing sweet FA, with little intelligence to analyse what is in front of them

Water Systems (Drivel) wrote this, and I would suggest that it describes him perfectly.

He never. I agree with him though.

 

[Doctor Drivel]

can't agree with the thermal store being better than unvented

the thermal store loses working temperature very quickly the minute water is drawn through it. my experience is the unvented cylinder holds a workable temperature for a longer period.

all the complaints that i have dealt with have been thermal stores that had been installed by 3 now defunct companies i have never been to a complaint about an unvented cylinder

Thermal stores and heat banks are different. Thermal stores have an immersed coil for DHW take off and heat banks a super efficient plate heat exchanger. Heat banks are far better. They do not loose working temperature easily at all. When they cool, the boiler comes in full on and puts its heat right at the top of the cylinder where it is needed for DHW take off to the plate. In effect the energy of the heat store and boiler are being combined.

A plate heat exchanger is so efficient, it can operate at a temperatures only 10C above the DHW temp required. If 50C DHW temp is needed then only 55C is needed in the stored water. They extract so much heat from the stored water and transfer it to the incoming cold mains water that the returing water temperature to the store is around 20C. Heat banks operate at a wide usful temperature range. The lower temperaures at the bottom of the cylinder promote condensing efficiency in boilers.

An unvented cylinder is far inferior in many ways to a heat bank. The boiler connected directly to a heat bank is operting in a far superior hydraulic environment and a natural neutral point and buffer is provided. A heat bank provides many great advantages all in one package. One of the greatest innovations in heating/hot water for many decades. Get to understand them.

 

[Doctor Drivel]

At first sight that sounds like nonsence but I can explain what Kevin means!

Because it is, when referring to heat banks.

An unvented is tall and thin and hot water taken from the top will be at the stored temperature until you get to the last 10% or so when some mixing occurs with the cold inlet water.

Heat banks can be tall and thin too.

The thermal store outputs the stored heat from a coil neat the top or a pumped plate HE and the whole store contributes to that heat transfer.

Thermal stores and heat banks operate differently in DHW take off and heat transfer.

If the store starts at 80 C then when half the heat has been taken out the store temp will have dropped to just 50 C. At such a low temperature the differential of about 10 C across the HE will mean that the maximum output temperature falls to just 40 C.

Stratification means that the top will be hotter than the bottom.

<snip the rest as it is inaccurate>